Tip #2 - Cool the power supply

The most common malfunction with one of these transceivers (also with the TS-930/940) is the failure of the 24 (or in the case of the Kenwoods, 28) volt section of the power supply, this due to the cooling fan becoming sluggish or inoperable - leading to a rise in pass-transistor temperature and eventual breakdown, which puts full supply voltage on the PA devices. Things tend to go bad at this point. From a number of years of run-time with the FT-980, I can attest to the fact that their onboard supplies run at an elevated temperature. The PA cooling fan (which also cools the PSU) will occasionally turn on even if the rig is just receiving.

There are several fixes for this, ranging from the quick-cheap-dirty to the complex and elegant. Time, money and space dictate the way to go here.

Simplest approach: An external muffin fan

I have a number of Drake FA-7 fans floating around the parts stash at any given time. These are a low-volume 110VAC Papst unit, originally designed to cool the TR-7, PS-7 and TR-5 equipment. Behind each of my FT-980s in the lineup there's an FA-7 sitting on a computer mouse pad (to deaden noise) and this is set to blow towards the power-supply area of the radio.

Intermediate approach: Rework the PSU cooling arrangement

A one-piece metal cover extends across both PA and PSU heatsinks. this can be cut in half, the PA side replaced and a frame which will hold two 70mm, 24VDC computer fans attached in its place. Mine will consist of sections of 1/2" aluminum angle, joined with low-temp aluminum brazing rod then painted or powdercoated after all mounting holes are located and drilled. A center plate is also required to cover a gap between the fans and this can be fabricated from aluminum. Power is taken from inside the radio through a jack installed in a mounting plate; the plate uses an existing (blank) hole in the rear panel that was covered with tape during factory assembly. This plate will also be used to mount an RCA jack for a panadapter output - more on that (plus pictures) to follow.

Most complex approach - Remote the power supply

Two operating voltages are sourced by the OEM PSU: 24V@15A max, and 12V@5A max. The entire PSU assembly can be removed from the radio, installed in an SP-980 speaker enclosure and cabled to the transceiver. Bulkhead-style Anderson Powerpoles would be ideal for either end of the circuit. Similarly, a pair of Quint switching power supplies (24V@20A and 12V@5 or 10A) are small enough to fit in an SP-980. Use the same bulkhead-connector approach to couple the units together.

It's too bad that Compudigital doesn't offer a drop-in switching-supply solution for the FT-980 as they do for the TS-9x0 series. I converted my '930 a couple of years ago and never looked back.